Flowserve Limitorque Actuators: General Safety Precautions and Practices

Limitorque multi-turn actuator.

The following are general guidelines for safely operating Limitorque actuators. This post is intended to supplement Flowserve / Limitorque's ongoing efforts to provide information on the safe and proper use of electric valve actuators on industrial globe, gate, ball, butterfly and plug valves.  It is critically important to always refer to the installation & maintenance manual before applying, installing and servicing Limitorque actuators. If unsure about any of the recommended safety or installation procedures, contact a factory authorized technician before going any further.

More than 1 million Limitorque actuators have been installed around the world, and some have been in operation for more than 50 years. The ruggedness and reliability of Limitorque electric actuators are among the primary reasons that customers continue to select Limitorque products.

Actuators requiring 90° of rotation to operate are necessary for quarter-turn valves such as ball, butterfly, plug and dampers, and rotary control valves. These types of Limitorque electric actuators are available for operations such as open-close, modulating, network and rotary service.

Multi-turn actuators are required to operate various types of rising stem valves such as gate, slide-gates, globe, check and linear control valves. These types of Limitorque electric actuators are available for operations such as open-close, modulating, network and linear service.

General Safety Precautions

1. Warning: Read the Installation and Maintenance Manual carefully and completely before attempting to install, operate, or troubleshoot the Limitorque actuator.
2. Warning: Be aware of electrical hazards. Turn off incoming power before working on the actuator and before opening the switch compartment.
3. Warning: Potential HIGH PRESSURE vessel — be aware of high-pressure hazards associated with the attached valve or other actuated device when installing or performing maintenance on the actuator. Do not remove the actuator mounting bolts from the valve or actuated device unless the valve or device stem is secured or there is no pressure in the line.
4. Warning: For maintenance and/or disassembly of the actuator while installed on the valve, ensure that the actuator is not under thrust or torque load. If the valve must be left in service, the valve stem must be locked in such a way as to prevent any movement of the valve stem.
5. Warning: Do not attempt to remove the spring cartridge cap, housing cover, or stem nut locknut from the actuator while the valve or actuated device is under load.
6. Warning: Do not manually operate the actuator with devices other than the installed handwheel and declutch lever. Using force beyond the ratings of the actuator and/or using additive force devices such as cheater bars, wheel wrenches, pipe wrenches, or other devices on the actuator handwheel or declutch lever may cause serious personal injury and/or damage to the actuator and valve.
7. Warning: Do not exceed any design limitations or make modifications to this equipment without first consulting Limitorque.
8. Warning: Actuators equipped with electrical devices (motors, controls) requiring field wiring must be wired and checked for proper operation by a qualified tradesman.
9. Warning: Use of the product must be suspended any time it fails to operate properly.
10. Caution: Do not use oversized motor overload heaters. Instead, look for the cause of the overload.
11. Caution: Do not operate the valve under motor operation without first setting or checking the limit switch setting and motor direction.
12. Caution: Do not force the declutch lever into the motor operation position. The lever returns to this position automatically when the motor is energized.
13. Caution: Do not depress the declutch lever during motor operation to stop valve travel.
14. Caution: Do not use replacement parts that are not genuine Flowserve Limitorque parts, as serious personal injury and/or damage to the actuator and valve may result.
15. Caution: Do not lift actuator/gearbox or actuator/valve combinations with only the eye bolts in the SMB actuator. These eye bolts are designed for lifting the SMB actuator only.

General Safety Practices

The following check points should be performed to maintain safe operation of the actuator:

1. Eye bolts in SMB and SB actuators are designed for lifting only the actuator and not associated gearboxes or valves.
2. Mount the actuator with the motor in a horizontal plane, if possible.
3. Keep the switch compartment clean and dry.
4. Keep the valve stem clean and lubricated.
5. Set up a periodic operating schedule for infrequently used valves.
6. Verify all actuator wiring is in accordance with the applicable wiring diagram.
7. Carefully check for correct motor rotation direction. If the valve closes when open button is pushed, the motor leads may have to be reversed.
8. Verify the stem nut is secured tightly by the locknut and that the top thread of the locknut is crimped or staked in two places.
9. Use a protective stem cover. Check valve stem travel and clearance before mounting covers on rising stem valves.

Mead O'Brien Authorized
Blue Ribbon Limitorque Parts & Service

For more information, or if you need field support with any Limitorque actuator, parts, or service, contact one of the following Mead O'Brien offices: 

www.meadobrien.com

Mead O’Brien, Inc.
10800 Midwest Industrial Blvd
St. Louis, Missouri 63132
(314) 423-5161

Mead O’Brien, Inc.
1429 Atlantic
North Kansas City, MO 64116
(816) 471-3993

Mead O’Brien, Inc.
16 South Main Street
PO Box 1086
Calvert City, Kentucky 42029-1086
(270) 395-7330

Mead O’Brien, Inc.
824 West Elgin
Broken Arrow, Oklahoma 74012
(918) 251-1588

A Better Alternative to Magmeter for Unpolished Condensate Flow Measurement

Veris Accelabar 

A large University was using magnetic flowmeters (Magmeters) to measure the flow of boiler feed water downstream of a condensate polisher. There were occasional system upsets that required the condensate polisher to be bypassed. When this happened, large amounts of debris would be released downstream and pass directly through the Magmeter, causing a build-up of foreign material on the internal sensing surfaces.

A magnetic flowmeter uses an electric current applied to a coil which produces a magnetic field. When conductive liquid flows through the magnetic field, a small voltage, proportional to the liquid velocity, is induced. As long as the interior surfaces of the Magmeter are clean and unobstructed, the meter accurately measures flow. If they get dirty or coated, all bets are off.

It was in the above mentioned upset situations where the University maintenance people were having problems. When upsets occurred, and the condensate polisher had to be by-passed, it meant the Magmeter would also have to be serviced because accuracy could no longer be guaranteed. Servicing the Magmeter was slow and costly. It meant shutting down the line, draining the pipe, removing the flowmeter, cleaning, and then putting it all back together.

Armstrong International’s Veris Group was called in for a consult. After review,  the Veris Group recommended installing an Accelabar® flow meter to offer an alternative solution that could provide reliable flow measurement regardless of an upset condition like unpolished condensate. The Accelabar provided a flow range of 22.5:1 turndown in flow, in a limited straight run scenario. In the past, two transmitters were required to provide the best accuracy across the entire range of the Accelabar. Veris was able to use the Foxboro IDP 10S with its FoxCal™ technology in order to have a combined percent of rate accuracy solution.

The new transmitter installation has 11 separate calibrations loaded into the device. As the differential pressure from the primary element is measured, the transmitter chooses the correct calibration curve. Veris’ solution delivered performance that was previously unattainable with a single differential pressure transmitter.

The Accelabar and Foxboro combined to be best solution, and the Accelabar flow meter is now the University's standard for the boiler feed water measurements.

For more information, contact:

Mead O'Brien, Inc.
10800 Midwest Industrial Blvd
St Louis,  MO 63132
314-423-5161
314-423-5707
www.meadobrien.com

Choose Guided Wave Radar for Your Challenging Process Level Application

Guided Wave
Radar Transmitter
Courtesy of
Foxboro/Schneider
Electric

Designed to perform continuous level measurement in a wide range of industries and applications, Guided Wave Radar transmitters (GWR) are unaffected by changes in temperature, specific gravity, pressure and with no need to recalibrate, offering a highly available measurement at low maintenance cost. GWR transmitters provide level measurement solutions in a variety of process applications, providing a universal radar measurement solution for all liquids including corrosive, viscous, sticky and other difficult media such as foam and turbulent surfaces, and solids.

Electromagnetic pulses are emitted and guided along a probe.  These pulses are reflected back at the product surface.  The distance is calculated by measuring this transit time. This device is perfect for high-end applications.  It is suitable for applications with foam, dust, vapor, agitated, turbulent or boiling surfaces with rapid level changes.

Common features include:
Easy configuration via digital communication; Wide selection of materials facilitates service under harsh/corrosive conditions; Solutions for density/pressure variations and rapid level changes; Empty Tank Spectrum filtering; Quick Noise scanning reduces false radar reflections.

Applications: Steam Generation /Boiler Drum; Oil/Water Separator; BioDiesel Production; Overflow Protection; Interface and Density; Process tanks; Storage tanks; Polyester/Nylon fiber production; Claus Process


For more information on Guided Wave Radar level instruments, contact:

Mead O'Brien
(800) 892-2769
www.meadobrien.com

Part 3: What Steam Is, How Steam is Used, and the Properties of Steam

Mead O'Brien Steam Experts

Steam is the gaseous phase (state) of water and has many domestic, commercial, and industrial uses. There are two categories of steam - wet steam and dry steam. In dry steam, all the water molecules stay in the gaseous state. In wet steam, some of the water molecules have released their energy (latent heat) and begin condensing into water droplets.

Steam, usually created by a boiler burning coal or other fuels, became the primary source of energy for mechanical movement during the industrial revolution, ultimately being replaced by fossil fuels and electricity.

Steam has many commercial and industrial uses. In agricultural, steam is used to remediate and sterilize soil. In power generation, approximately 90% of our electricity is created using steam as the working fluid to spin turbines. Autoclaves use steam for sterilization in microbiology labs, research, and healthcare facilities. Many commercial and industrial pieces of equipment are cleaned with steam. Finally, commercial complexes, campuses and military buildings use steam for heat and humidification.

The following video, the FINAL part of a three part series titled “What Steam Is, How Steam is Used, and the Properties of Steam” provides the viewer with an exceptional basis to build from. Special thanks to Armstrong International who created the original work.

For more information on any industrial or commercial steam application, contact:

Mead O'Brien, Inc.

www.meadobrien.com

(800) 892-2769

Part 2: What Steam Is, How Steam is Used, and the Properties of Steam

Steam is the gaseous phase (state) of water and has many domestic, commercial, and industrial uses. There are two categories of steam - wet steam and dry steam. In dry steam, all the water molecules stay in the gaseous state. In wet steam, some of the water molecules have released their energy (latent heat) and begin condensing into water droplets.

Steam, usually created by a boiler burning coal or other fuels, became the primary source of energy for mechanical movement during the industrial revolution, ultimately being replaced by fossil fuels and electricity.

Steam has many commercial and industrial uses. In agricultural, steam is used to remediate and sterilize soil. In power generation, approximately 90% of our electricity is created using steam as the working fluid to spin turbines. Autoclaves use steam for sterilization in microbiology labs, research, and healthcare facilities. Many commercial and industrial pieces of equipment are cleaned with steam. Finally, commercial complexes, campuses and military buildings use steam for heat and humidification.

The following video, the second part of a three part series titled “What Steam Is, How Steam is Used, and the Properties of Steam” provides the viewer with an exceptional basis to build from. Special thanks to Armstrong International who created the original work.

For more information on any industrial or commercial steam application, contact:

Mead O'Brien, Inc.

www.meadobrien.com

(800) 892-2769

Part 1: What Steam Is, How Steam is Used, and the Properties of Steam

Steam is the gaseous phase (state) of water and has many domestic, commercial, and industrial uses. There are two categories of steam - wet steam and dry steam. In dry steam, all the water molecules stay in the gaseous state. In wet steam, some of the water molecules have released their energy (latent heat) and begin condensing into water droplets.

Steam, usually created by a boiler burning coal or other fuels, became the primary source of energy for mechanical movement during the industrial revolution, ultimately being replaced by fossil fuels and electricity.

Steam has many commercial and industrial uses. In agricultural, steam is used to remediate and sterilize soil. In power generation, approximately 90% of our electricity is created using steam as the working fluid to spin turbines. Autoclaves use steam for sterilization in microbiology labs, research, and healthcare facilities. Many commercial and industrial pieces of equipment are cleaned with steam. Finally, commercial complexes, campuses and military buildings use steam for heat and humidification.

The following video, the first part of a three part series titled “What Steam Is, How Steam is Used, and the Properties of Steam” provides the viewer with an exceptional basis to build from. Special thanks to Armstrong International who created the original work.

For more information on any industrial or commercial steam application, contact:

Mead O'Brien, Inc.
www.meadobrien.com
(800) 892-2769

Coriolis Flowmeter Reduces Sucrose Losses with Better Molasses Production at Sugar Mill

Molasses Production at Sugar Mill

A sugar mill typically loses between one and two percent of its incoming sucrose to factors such as poor clarification, sugar crystal elongation, reduced crystal growth rates, filter cake loss, and loss to molasses. Of these, loss to molasses is most significant — and one of the most difficult to prevent. Loss to molasses results from inaccurate flow measurement that causes more than the required amount of sucrose to pass into the molasses recipe. Wasting valuable sucrose can directly affect profitability of molasses batch yields, so new strategies to control this loss are constantly being investigated.

Improved control begins with a reliable measurement of molasses production, but getting that is indeed a challenge. Estimating undetermined sugar loss to within 0.1 percent, for example, requires molasses loss measurement that is accurate to at least one percent.

There are a number of methods that have been employed to measure molasses quantities in sugar mills around the world, each with distinct advantages and limitations. Measuring storage tank levels on a regular basis is probably the simplest method, but readings are inconsistent and unreliable. The error in the mass estimate affects the undetermined loss directly. Further complicating accuracy are chemical reactions that produce carbon dioxide, which affects both density and tank levels.

Another method is production tank dipping, which involves detecting changes in ow based on changes in torque at various measurement points. While this may be adequate for reporting on a volume basis, most molasses production balance is based on mass. Also, molasses is usually aerated, which creates two-phase flow conditions, further compromising density and accuracy.

Foxboro Coriolis Flowmeter

Engineers at this sugar mill compared measurements made by tank dipping and batch weighing to conventional and digital Coriolis measurements at various points over a three-year period. Years earlier, they installed a competitor’s conventional Coriolis meter. Shortly after, they installed a Foxboro CFT50 digital Coriolis transmitter from Foxboro in series with the existing unit. The Foxboro meter uses digital flowtube control that overcomes flow interruption or stalling caused by two-phase flow. And finally, a short time later, as a benchmark for accuracy, they installed a set of molasses batch scales. Valve leaks notwithstanding, they assumed that the scales would provide the most faithful measure of flow.

The measurements from tank dipping were ten to fifteen percent lower than estimates obtained from either of the Coriolis meters tested.

Later, with the batch scales installed, both Coriolis meters recorded consistently higher estimates than the scales readings. On average, the Foxboro meter gave readings that were three percent higher, and the conventional meter read nine percent higher.

It was clear that the Coriolis meters followed the batch scales much more closely. This strongly indicates the unreliability of tank dipping measurements and suggests that the Coriolis meters are also more responsive to real changes in flow rate. An unanticipated result also indicated that the digital Coriolis meter might be the most responsive to sudden changes in flow rate.

While acknowledging the need for additional study, the researchers concluded that Coriolis measurement is the only suitable alternative to batch scales for measuring sucrose loss to molasses. They found that the conventional Coriolis meter tended to estimate higher than the Foxboro Coriolis meter and that the Foxboro meter had a significantly faster response time in on/off applications.